Compressor lubricating system



July 3, 1934. D E, MACCABEE I 1,965,198

COMPRESSOR LUBRICATING SYSTEM Filed Julyf', 1933 llllllllllllllllPatented July 3, 1934 1,965,198 l comensson Lnnrcarnvc SYSTEM David E.Maccabee, Chicago, DI., assignor to Stewart-Warner Corporation, Chicago,lill., a corporation of Virginia Application JnLv lIZ, 1933, Serial No.679,316

iiCla-ms.

This invention relates to improvements in refrigerant compressors andlubricating systems therefor.

It is an object of my invention to provide a system in 4which lubricantis continuously circulated with the refrigerant.

It is further an object of my invention to construct the refrigerantcompressor in such a manner that the incoming cold vapor is conducted lothrough the driving member for the compressor for the purpose of coolingthe bearings therefor.

Another object of my invention is to provide similar refrigerantcompressors in which the crank shaft is formed with an axial intakepassage into which the incoming cold refrigerant vapor, containing somerefrigerant, is delivered and to further provide ducts in the crankshaft for delivering the cold refrigerant and lubricant to the bearingsfor the crank shaft whereby the refrigerant and lubricant is finallydrawn by suction into the crank case cavity from which it is drawn intothe cylinders for compression and delivery from the compressor casing.

Further objects and advantages of my improvements will be more readilyapparent from the folowing description taken in connection with theattached drawing, in which Figure 1 is a somewhat diagrammatic view ofthe refrigerating system showing the reservoir 8O in vertical sectionand the compressor in partial vertical section, and I Figure 2 is ahorizontal section on an' enlarged scale of the refrigerant compressor.

The refrigerating systemincludes a two-cylinder compressor from whichthe high pressure refrigerant vapor containing lubricant is deliveredthrough the pipe l2 to the condenser coil 14, to be cooled by the fan16. The condensed refrigerant containing lubricant is then deliveredthrough the pipe 18 to a reservoir 20 past a shutoli valve 22. Withinthe reservoir 2G the refrigerant liquid containing some lubricantcollects at the bottom While the excess lubricant containing a smallpercentage of refrigerant collects as a floating layer within thereservoir. 'Ihe outlet tube 24 surrounded by the screen 26 draws olifthe refrigerant liquid containing a small percentage oi lubricant fromthe bottom of the reservoir. The fluid is delivered past the outletshut-olf Valve 28 through a pipe 30 to an expansion Valve 32. The lowpressure refrigerant vapor containing lubricant flows through theevaporator 34 and is iinally delivered through the pipe .'36 to theinlet of the compressor.

I have found that it is highly desirable to cirpermit free ow of therefrigerant Vapor from culate some lubricant l with the refrigerantthrough the entire system. It `seems that a muchv more unifcrm coolingaction is obtained throughout the length of the evaporator coil due tothe fact that the lubricant appears to carry through some of therefrigerant so that the refrigerant does not become completely vaporizedat the inlet only of the evaporator and the cooling action is continuousthroughout a considerable portion of the length of the evaporator.Referring now. to the construction ofthe refrigcrant compressor as shownin Figure 2, the compressor casing 38 includes a pair of oppositelydisposed cylinders 40 having annular cooling ribs 42. The crank shaft 44is driven by the pulley 46 held by key 48 and nut 50 to the outer end ofthe crank shaft. The bearing housing 52 is secured to the compressorcasingA by bolts 54 and has mounted therein a bearing sleeve 56 forsupport of one end of the crank shaft.

The cavity 5s in the housing 52 will provide 75 space for the provisionof sealing means comprising a ring 6) having a knife-edge contact at 62with a shoulder 64 of the crank shaft. Bearing 60 has secured thereto aanged disk 66 which forms a seat for the inner end of a coil spring 68reacting at its outer end against a disk 70 held in seated position bythe cap 72 fastened by bolts '74. A metallic sealing bellows 76 iswelded at its inner end to the hanged ring l66 and at its 85 outer endto the disk 70. It will be understood that the spring ring 68 maintainsa sealing contact between the ring 60 and the crank shaft 44. Passage 78is provided through the housing 52 to the cavity 58 and into the crankcase cavity 80. 90

The pistons 82 are mounted in the cylinders 40 andare operated byconnecting rods 84 from an eccentric 86 on the crank shaft. The crankshaft may have a counter-balance 88. The inner end of the crank shaft issupported by bearing sleeve 90 and a ball thrust bearing 92 is alsoprovided. The ball bearing 92 seats upon a disk 94 formed withperforations 96; It will be noted that the crank shaft 44 has alongitudinal passageway 98 and its inner end is notched as at 100 toprovide a seat for the ball bearing 92 but still .permit freeV passageof the refrigerant vapor and CJJ bricant flows longitudinally throughthe crank shaft. The crank shaft has a radial passageway 108 leading tothe bearing sleeve 90. Radial passages 110 lead to the bearings for theconnecting rods 84 which, in turn, are provided with diagonally disposedducts 112. Finally the outer end of the crank shaft is formed with aplurality of radial passages 114 whereby the refrigerant vapor andlubricant which has not been delivered through the first-mentionedradial passage will escape adjacent the outer bearing sleeve 56 foi` thecrank shaft. It will be understood that the refrigerant vapor andlubricant will perform the dual function of cooling and lubricating thecrank shaft and its bearings and finally reachesl the crank case cavity80.

Figure 1 illustrates the manner in which the refrigerant vapor andlubricant is ldrawn into the cylinders 40 through the horizontalpassageways 116 andthe notched inlets 118 opening into the cylindercavities. The compressed. refrigerant vapor and lubricant is deliveredthrough outlet check valves 120. Each check valve 120 is positioned bystuds 122 on a supporting ring 124 and coil springs 126 are providedpositionedby the studs and reacting upon the valve 120 to normally holdthe valve in seated position. The check valve and spring assembly isretained in place by a cap member 128 secured to the cylinder by bolts130. The compressed refrigerant and lubricant is finally deliveredthrough the passageways 132- 134 to the outlet connection 136 of the capmember 138 secured by bolts 140.

As another feature I may employ small bleed openings 142 in the heads ofthe pistons. This will provide for easyv starting of the compressor bypermitting a small portion of the refrigerant vapor to iiow back intothe crank case cavity.

In operation the cold refrigerant vapor and lubricant is drawn into thecompressor casing due to the high suction maintained in the crank casecavity. The cold refrigerant vapor will keep the bearings of therotatable crank shafts cool and the lubricant will pass through all, ofthe bearings. Although some of the lubricant may collect in the crankcase cavity, I do not provide a large lubricant reservoir, as iscustomary practice, but, instead, intend to circulate the lubricant withthe refrigerant. The cold.loW pressure refrigerant together withentrained lubricant is therefore drawn into the cylinders and compressedby the action of the pistons and is then conducted to the high pressureside of the system. The refrigerant vapor is condensed and finally flowstogether with the lubricant into the reservoir where the,v lubricantsaturated refrigerant settles out. The excess lubricant containing somerefrigerant collects above or below the surface of the lubricantsaturated liquid, dependent upon the specific gravities of the liquidsused. As the refrigerant vapor is drawn from the evaporator, refrigerantliquid and lubricant are supplied through the expansion valve.

I claim:

1. In a refrigerant compressor, a casing, a crank shaft rotatablysupported in said casing, a thrust bearing for the inner end of saidcrank shaft, said crank shaft having a passage extending therein fromthe inner end thereof and means for circulating low pressure refrigerantvapor and lubricant around said thrust bearing and into the passage ofsaid crank shaft.

2. In a refrigerator compressor, a casing including a crank casingcavity, a rotatable crank outer end of said crank shaft and saidcasing,said y crank shaft having a longitudinal passage open at theinner end thereof, means for delivering low pressure cold refrigerantvapor into said casing and around said thrust bearing into the crankshaft passage, means for conducting the refrigerant vapor from saidcrank shaft passage to said bearings and means operated by said crankshaftv for compressing the refrigerant vapor drawn from said crank casecavity and delivering the refrigerant from the casing.

3. In a refrigerant compressor, a casing including a cylinder and acrank case cavity, a piston in said cylinder, a crank shaft rotatablysupported in said casing and connected to said piston, an axial passagein said crank shaft, an inlet through said casing into communicationwith said passage in said crank shaft, a communication between the crankshaft passage and the crank case cavity for the passage of therefrigerant vapor, an inlet passage from said crank case cavity intosaid cylinder and an outlet passage from the cylinder for the deliveryof the compressed refrigerant vapor.

4. In a refrigerant compressor, a casing including a pair of cylinderchambers and a crank case cavity, pistons reciprocable in saidcylinders, a crank shaft rotatably mounted in said casing and 4extendingoutwardly thereof, sealing means between said crank Shaft and saidcasing at one end of said crank case cavity, connecting rods betweensaid crank shaft and said pistons, said crank shaft having alongitudinal passage formed therein, a refrigerant inlet through saidcasing into communication with one ,end of said crank shaft passage,communicating ducts between portions of said crank shaft passage andsaid crank case cavity, inlet passagesV leading from said crank casecavity to said cylinders and outlet passages for the delivery of thecompressed refrigerant from said cylinders.

5. In a refrigerant compressor, a casing including cylinder chambers anda crank case cavity, pistons reciprocable in said cylinders, a rotatablecrank shaft extending into said casing, sealing means between saidrotatable crank shaft and said casing, spaced bearings for said crankshaft within said casing beyond said sealing means, inlet means fordelivering the refrigerant vapor and lubricant through said crank shaftto said bearings whereby said refrigerant vapor and lubricant finallyreaches the crank case cavity, inlet passages from said cavity to saidcylinders and outlet passages from said' cylinders for the delivery ofthe compressed refrigerant. s

6. In a refrigerant compressor, a casing, a cylinder in said casing, apiston reciprocable in said cylinder, a crank shaft rotatably supportedin said casing, sealing means between said crank shaft and said piston,said casing having a crank case cavity surrounding the crank shaft, aninlet for the refrigerant vapor into said crank case cavity, an inletpassage from said cavity to said cylinder, an outlet passage for thedelivery of compressed refrigerant from said cylinder and metering meansin said piston for bleeding back into the crank case cavity a portion ofthe refrigerant being compressed in said cylinder.

DAVID E. MACCABEE.

